Microsoft Security Bulletin MS16-047 - Important

10/11/20175 minutes to readContributors

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Security Update for SAM and LSAD Remote Protocols (3148527)

Published: April 12, 2016

Version: 1.0

Executive Summary

This security update resolves a vulnerability in Microsoft Windows. The vulnerability could allow elevation of privilege if an attacker launches a man-in-the-middle (MiTM) attack. An attacker could then force a downgrade of the authentication level of the SAM and LSAD channels and impersonate an authenticated user.

The security update addresses the vulnerability by modifying how the SAM and LSAD remote protocols handle authentication levels. For more information about the vulnerability, see the Vulnerability Information section.

Affected Software and Vulnerability Severity Ratings

The following software versions or editions are affected. Versions or editions that are not listed are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, see Microsoft Support Lifecycle.

The severity ratings indicated for each affected software assume the potential maximum impact of the vulnerability. For information regarding the likelihood, within 30 days of this security bulletin’s release, of the exploitability of the vulnerability in relation to its severity rating and security impact, please see the Exploitability Index in the April bulletin summary.

[2]Windows 10 updates are cumulative. The monthly security release includes all security fixes for vulnerabilities that affect Windows 10, in addition to non-security updates. The updates are available via the Microsoft Windows Update Catalog.

*The Updates Replaced column shows only the latest update in any chain of superseded updates. For a comprehensive list of updates replaced, go to the Microsoft Update Catalog, search for the update KB number, and then view update details (updates replaced information is provided on the Package Details tab).

Update FAQs

My application or product uses the SMB protocol, does this issue affect me?No. Only applications and products that use the SAM or LSAD remote protocols are affected by this issue. The SMB protocol is not vulnerable.

Vulnerability Information

Windows SAM and LSAD Downgrade Vulnerability- CVE-2016-0128

An elevation of privilege vulnerability exists in the Security Account Manager (SAM) and Local Security Authority (Domain Policy) (LSAD) remote protocols when they accept authentication levels that do not protect them adequately. The vulnerability is caused by the way the SAM and LSAD remote protocols establish the Remote Procedure Call (RPC) channel. An attacker who successfully exploited this vulnerability could gain access to the SAM database.

To exploit the vulnerability, an attacker could launch a man-in-the-middle (MiTM) attack, force a downgrade of the authentication level of the SAM and LSAD channels, and then impersonate an authenticated user. The security update addresses the vulnerability by modifying how the SAM and LSAD remote protocols handle authentication levels.

The following table contains links to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list:

Security Update Deployment

Acknowledgments

Microsoft recognizes the efforts of those in the security community who help us protect customers through coordinated vulnerability disclosure. See Acknowledgments for more information.

Disclaimer

The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.